This invention relates to compositions for coating paper, hardboard, fiberboard, paperboard, and molded-pulp products.
The present invention relates to compositions for coating paper and related pulp-based products. The compositions of the invention are aqueous compositions, usually in the form of suspensions comprising at least one of the following: a clay, a starch, casein, a resin, and a wax, and containing one or more of a branched reaction product comprising the following reactants:
A) at least one compound of formula I
R1(X)3xe2x80x83xe2x80x83(I)
xe2x80x83wherein each X group is a halogen atom or one X group is a halogen atom and two X groups represent an epoxy oxygen atom, which is attached to two adjacent carbon atoms in the R1 group to form an epoxy group, and R1 is an alkanetriyl group containing from 3 to 10 carbon atoms; and
B) at least one compound having the formula II
R2X(AO)nYxe2x80x83xe2x80x83(II)
xe2x80x83wherein R2 is a substituted or unsubstituted, saturated or unsaturated, organic group having from 1 to 36 carbon atoms; X is xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, or xe2x80x94NR3xe2x80x94 where R3 is hydrogen or a C1-C18 alkyl group; each AO group is independently an ethyleneoxy, 1,2-propyleneoxy, or 1,2-butyleneoxy group, n is a number of from 0 to 200, preferably from 1 to 100, more preferably from 2 to 20; and Y is hydrogen, or Y can be a mercapto group or an amino group (amino or C1-C6 alkylamino group) in place of a terminal xe2x80x94OH group, provided that when Y is mercapto or an amino group or a C1-C6 alkylamino group, n is at least 1;
wherein the mole ratio of the linking compound A) to B) is from 0.1:1 to 5:1, preferably from 0.6:1 to 2:1, more preferably from 0.8:1 to 2:1 and most preferably from 0.8:1 to 1.5:1.
Paper coating compositions containing one or more of the above reaction products results in the minimization or elimination of fisheyes, excellent flow and leveling properties, and marked reduction or elimination of foam. In addition, coating open time is extended without affecting either wet strength of the paper or its gloss when dry.